Blast room with uniform down-draft ventilation



1968 D. TEMPLE ETAL 3,407,719

BLAST ROOM WITH UNIFORM DOWN-DRAFT VENTILATION Filed April 28, 1967 5 Sheets-Sheet 1 FIG. 2

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INVENTOIQS DONALD L. TEMPLE BY NATHAN 08E Oct. 29, 1968 o. L. TEMPLE ETA'L 3,407,719

BLAST ROOM WITH UNIFORM DOWN-DRAFT VENTILATION Filed April 28, 1967 5 Sheets-Sheet 2 FIG. 3

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lNVENTORS DONALD L. TEMPLE NATHAN OBERG Oct. 29, 1968 D. L. TEMPLE ETAL 3,407,719

BLAST ROOM WITH UNIFORM DOWNDRAFT VENTILATION Filed April 28, 1967 5 Sheets-Sheet 5 INVENTOBS DONALD L. TEMPLE FIG. 6 NATHAN 081: x

A TTQRAIEKS 1968 D. TEMPLE ETAL 3,407,719

BLAST ROOM WITH UNIFORM DOWN-DRAFT VENTILATION Filed April 28, 1967 5 Sheets-Sheet 4.

INVENTDRS FIG. 9 DONALD 1.. TEMPLE NATHAN came v Oct. 29, 1968 D. TEMPLE ETAL 3,407,719

BLAST ROOM WITH UNIFORM DOWNDRAFT VENTILATION Filed April 28, 1967 5 Sheets-Sheet 5 DONALD L. TEMPLE B NAT/MN ORE/2G ATTORNEYS United States Patent 3,407,719 BLAST ROOM WITH UNIFORM DOWN-DRAFT VENTILATION Donald L. Temple and Nathan Oberg, Washington, M0.,

assignors to Zero Manufacturing Company, Washington, Mo., a corporation of Missouri Filed Apr. 28, 1967, Ser. No. 634,586 7 Claims. (CI. 9832) ABSTRACT OF THE DISCLOSURE A blast room which has air drawn through a pervious top downwardly through a perforated floor and means for separating and exhausting the air and collecting the blasting material. The top is louvered by three tiers of angle beams resting on supports and alternately disposed so that an upwardly directed air blast suflicient to lift a beam moves same to block the space between two adjacent beams in the tier above. The floor includes a perforated grating lying on detached and readily removable beams of M cross-section having apertures in the central lower apex, there being two inclined longitudinally extending plates within the beam on either side of said apex. In one embodiment the plates extend normally from the vertical legs of the beam. In another they are vertical. In a further embodiment an inclined angle beam is inverted above the apex of the M-beam with slots disposed along the edges of the angle beam.

Background of the invention This invention relates to an enclosed blast room for a fine particle system. More particularly, it relates to an improved blast room of modular unit construction having a one-way type louvered roof and floor components which are readily removable for cleaning or other purposes.

Fine particle blasting has enjoyed wide acceptance in the last several years, especially since the advent of dry glass bead peening and reclaim systems which effectively separate the blasting particles from dust and debris arising from the blasting operation. The glass bead particles range in size between DOGS-.026 inch diameter with diameters of .0035.0059" being popular for most applications. In recent years room-sized glass bead blasting chambers have made their appearance. Examples of such rooms are disclosed in Patent Nos. 2,912,918 and 3,026,789 issued Nov. 17, 1959 and Mar. 27, 1962, to W. H. Mead. Prior to this, rooms for abrasive blast systems such as disclosed in Patent No. 2,292,665 of Aug. 11, 1942, to C. B. Schneible, were well-known and contemporary glass bead blast rooms have been adaptations of these systems. However, the abrasive blast systems largely utilized sand, shot or grit blasting materials which were relatively large and usually expend-able. Glass beads and alumina oxides, however, present major packing and conveying problems in such a system. With known systems there is a tendency for overloading the sump and clogging, particularly in the floor area and when moisture is present. When such occurs, the lack of accessibility for cleaning is a major problem.

In addition, current roof designs either give insufficient protection against misdirected air blasts penetratin the roof, thus defeating the very purpose of the rooms or constitute an undue air restriction thus adversely affecting the static pressure of the system which, in turn, makes a larger blower necessary and has a negative influence upon the efficiency of the unit.

Summary of the invention The invention is directed to the structural units of 3,407,719 Patented Oct. 29, 1968 ice the roof and floor which, in the case of the roof, is unique in that it is sufiiciently opened to provide: an improved air flow in comparison with current roofs for similar installations and will automatically close in response to a misdirected air stream somewhat in the same fashion as louvers, thereby preventing dust from escaping into the surrounding atmosphere. Since the individual beams of the roof are not welded or otherwise fastened to the supporting structure, the roof can be installed with less expense and also more easily cleaned or dismantled or both.

The floor construction includes characteristics which provide a clog resistant duct for the evacuation of air,

blasting material and debris unless undue moisture is introduced. In such event, the floor beams which are not welded or otherwise fastened to the foundation plate or to each other can easily be lifted and cleaned. As with the roof, the floor can be quickly installed. The compact and inherently strong trusslike construction of the floor beams permits a reduction in floor height and eliminates the requirement for much of the supporting structure which might otherwise be necessary.

The primary object of the invention is to provide the above advantages by the structure as disclosed and claimed. However, other objects, adaptabilities and capabilities will be appreciated by those skilled in the art to which the subject matter of the invention pertains, reference being had to the accompanying drawings, in which:

Brief desription of the drawings FIGURE 1 is a schematic perspective view of a blast room in accordance with the invention;

FIGURE 2 is a cross sectional view of the blast room;

FIGURE 3 is a cross sectional view of a roof segment of the blast room;

FIGURE 4 is a fragmentary exploded perspective view showing two roof angle beam supporting means;

FIGURE 5 is a fragmentary perspective view of the floor design of the blast room;

FIGURE 6 is a front sectional view of a floor beam shown in FIGURE 5;

FIGURE 7 is a side sectional view of a floor beam shown in FIGURE 5;

FIGURE 8 is a fragmentary perspective view of a further embodiment of the floor design of the blast room;

FIGURE 9 is a front sectional view of a beam shown in FIGURE 8 with the apertures 74 omitted;

FIGURE 10 is a fragmentary perspective view of a still further embodiment of the floor design of the blast room; and

FIGURE 11 is a front sectional view of a beam shown in FIGURE 10.

Description of the preferred embodiments FIGURE 1 shows a blast room with conventional components comprising a separator and reclaim system 21 and a dry filter 22. The separator and reclaim system 21 is connected to the exhaust from the pickup snout 77 of blast room 20 by an exhaust conduit 24. The separator and reclaim system 21, the dry filter 22, and the exhaust The roof of the blast room is designated generally 32, and the floor is designated generally 34.

From FIGURE 1 it will be noted that the roof 32 comprises some eight modules 35. FIGURE 3 shows a cross section of a typical module 35 which includes a framework 36. Supported within the module 35 by the framework 36 are three tiers of angle beams designated 37. These angle beams 37 lie on tent-shaped supports 43 (see FIGURE 4) which are spot welded or otherwise fastened to the framework 36. Corresponding supports 43 are situated at both ends of the framework 36 so that each angle beam 37 spans a pair of the supports 43 located at the end of the framework 36. The angle beams 37 are composed of a thin gage metal (their thickness being exaggerated in the drawings) and are not secured to the supports 43 in the sense that they can be lifted freely from such supports. FIGURE 4 illustrates an end of an angle beam 37 on support 43, and a further support 43 without its angle beam in a lower tier. If a blast is inadvertently directed upwardly to impinge upon one of the angle beams 37 of tier 40, such angle beam is raised thereby into the space between the adjacent angle beams 37 directly above in tier 41. In the same manner a blast hitting an angle beam in tier 41 moves it into the corresponding spaces between the adjacent angle beams 37 next above in tier 42. As a result, substantially no portion of the blast is permitted to escape through the roof 32. A grating 44 is laid across the upper portion of the beams 37 of tier 42, as shown in FIGURE 3, which prevents the upward displacement of tier 42.

If desired, a loosely packed fibrous material mat 45 may be included within the framework 36 of each module 35 above the grate 44. Spanish moss is a satisfactory fibrous material for this purpose.

Protected lights 47 are secured to roof beams 50 which also function to receive and support the modules 35. As necessary and desired, utility inlets such as inlet 51 for blasting material and inlet 52 for fresh air supply to the operator are provided in the blast room 20.

. In a blast room designed in accordance with the invention, air is drawn vertically downward through the roof 32 into the floor 34 at a rate of about fifty-five feet per minute, This compares with a rate of about forty feet per minute in known practical designs. One reason that a relatively high air flow rate can be achieved without un' duly raising the static pressure on the blast room 20 lies in the design of the roof 32 as set forth above. However, of equal importance to the efiicient and effective operation of the blast room 20 is a floor structure whereby the air ladened with spent blasting material and other debris is continuously removed from the blast room 20 during blasting operations.

FIGURES 5, 6 and 7 show a preferred floor design embodiment. In this embodiment, floor beams 54, having an M-shaped cross section, are laid side by side across the foundation plate 57. The upper V of the M-shaped beams forms a hopper and at the lower apex of such hopper there are ,a plurality of slots 55 of sufiicient size to permit the continuous exhaustion from the blast room of air, blasting material and the debris resulting from the blasting operation. It has been found that slots /3" or M by /2 disposed longitudinally with respect to floor beams 54 and spaced a quarter of an inch apart are satisfactory. Angle irons 56 span adjacent pairs of the floor beams 54 and provide immediate support for floor gratings 62 which may have braces 64 affixed thereto. If desired, an angle iron 56 may be left exposed, as illustrated in FIGURE 5, whereby it also functions as a track to receive a wheeled work-supporting means such as dolly 65 as shown in FIG- URE 2. The dolly 65 is shown in FIGURE 2 supporting a work piece 66 being subjected to blasting treatment. Secured on either side of the slots 55 within the lower por tion of the floor beam 54 are right and left air divider plates and 61. These are securely fastened within the beam by welding or other appropriate means and are in- 4 clined relative to the longitudinal length of the beam so that, as seen in FIGURES 2 and 7, there is substantially more space between the foundation plate 57 on one hand and on the other the air divider plates 60 and 61 on the left-hand portion of the floor beams where air discharges into pick-up snout 77 than on the right-hand portion. It is preferable that the inclination be sufficient so that the velocity of the air moving horizontally to the left, as seen in FIGURE 2, under the air divider plates 60 and 61 is substantially uniform and similarly, air is drawn into the slots 55 at a substantially uniform velocity irrespective of their specific location in the blast room 20. It is preferred that the floor beam 54 be bevelled inwardly on the right end side, as seen in profile in FIGURES 2 and 7.

The angle irons 56 are not secured to the floor beams 54 which in turn are not secured to the foundation plate 57. Thus to remove the floor beams 54 or any particular fioor beam, all that is necessary is to lift and remove the associated floor grating 62, pick up and lay aside the angle irons 56, and lift out the floor beams 54, as desired.

It will be noted that the floor of this embodiment is a rib type floor supported by what is essentially a truss-like structure in the floor beams. The floor is compact in that it takes up little room, and floor assemblies can be added or deleted as required by the size of the particular blast room, or as otherwise may 'be desired for cleaning purposes.

FIGURES 8 and 9 show modified floor design. The same reference numerals have been used for parts similar to those previously described. In this embodiment, the floor beam 67 also has an M-shaped cross section. However, the central lower apex of the beam 67 is on the same level as the lower edges of the outer legs. A floor beam housing 70 receives the floor beam 67 and, if desired, may be secured thereto whereby a strong truss-like structure is formed. Within the V-portion of the floor beam 67 is received an inclined angle beam 71. The conveying duct 72 thus formed increases in size in the direction of the movement of air therein. Air is drawn uniformly into the duct 72 through a plurality of slot-like passages 74 of sufiicient size for that purpose. As in the prior embodiment, the various components are laid one upon the other so that the floor grating 62 is readily removable from the underlying supporting structure, the inclined angle beam 71 can be lifted from position for cleaning and, if desired, the floor beams 67 either with or separately from the floor beam housings 70, can be lifted and removed from the foundation plate 57.

A still further embodiment of the floor design is shown in FIGURES 10 and 11. Again the same reference numerals have been used for similar parts previously shown and described. The foundation plate 57 supports floor beam housings 70 in a side to side relation, each of which receives floor beams 54 of M-shaped cross section. The central lower apex of the beam 54 has a plurality of slots 55. Beam braces 75 may be secured to the floor beams 54 or to the gratings 62. In this particular embodiment, however, it is preferred that they be secured to the beams 54. Space is provided between selected beam braces 75 for the receipt of angle irons 56 which function as rails for dolly 65 or the like. A tapered air duct which is U-shaped in cross section lies under the slots 55. It increases in size in the direction of air carried therethrough to equalize the air velocity through the slots 55 and to provide the necessary space for conveying the blasting media to the pickup snout 77 of the blast room 20 and eventually to the reclaim system. As with the previous floor embodiments, the individual components can be removed merely by lifting same so as to provide ready accessibility for cleaning or other purposes.

While we have described preferred embodiments of our invention, it is to be understood that it is capable of other adaptations and modifications within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. A roof (32) for a blast room (20) which comprises:

supporting structure (36),

a first plurality (40) of angle beams (37) substantially of an inverted V cross-section horizontally disposed in a parallel side by side spaced relationship across said supporting structure,

a second similarly disposed plurality (41) of angle beams spaced above and parallel to said first plurality, the beams of said second plurality being disposed above the spaces between the adjacent beams of said first plurality, the beams of said first plurality being free from connections to said supporting structure and liftable therefrom whereby a blast of air directed upwardly and impinging upon one of said beams of said first plurality tends to lift such beam into a position which closes the proximate space immediately above such beam which is between the beams of said second plurality.

2. A roof in accordance with claim 1 wherein fibrous material (45) is disposed above said second plurality.

3. A roof in accordance with claim 1 wherein there is a third similarly disposed plurality (42) of angle beams spaced above and parallel to said second plurality, the beams of said third plurality being disposed above the spaces between the adjacent beams of said second plurality, the beams of said second plurality being free from connections to said supporting structure whereby a blast of air directed upwardly and impinging upon one of said beams of said second plurality tends to lift such beam into a position which closes the proximate space immediately above such beam which is between beams of said second plurality.

4. A roof in accordance with claim 3 wherein fibrous material is disposed above said third plurality.

5. A roof in accordance with claim 4 wherein a grating is disposed between said fibrous material and a grating carried by said third plurality.

6. A roof in accordance with claim 3 wherein the beams of said third plurality are free from connections to said supporting structure whereby said beams of said third plurality are liftably removable therefrom.

7. A blast room (20) comprising:

a casing providing a chamber,

a roof (32) of said casing including louvered means covering a substantial portion of said roof (37) to permit the intake of air into said chamber, an opening in said roof above said louvered means, said louvered means being movable by air directed upwardly against same whereby said louvered means closes said opening and the escape of air upwardly through said roof is substantially prevented,

a floor portion (34) of said casing being apertured to permit the escape of air,

means providing a chamber below said floor,

a suction conduit (77) communicating with said lower chamber and with a source of suction, and

means for collecting blasting substances passing through said floor.

References Cited UNITED STATES PATENTS ROBERT A. OLEARY, Primary Examiner.

r W. E. WAYNER, Assistant Examiner. 

